Thursday, March 29, 2007

Ice shelf

An ice shelf is a broad, balanced platform of ice that forms where a glacier or ice sheet flows down to a shoreline and onto the ocean surface, typically in Antarctica or Greenland. The border between floating ice shelf and the grounded ice that feeds it is called the grounding line. When the grounding line retreats inland, water is added to the ocean and sea level rises.

In contrast, sea ice is formed on water, is much thinner, and forms all through the Arctic Ocean. It also is bring into being in the Southern Ocean around the continent of Antarctica.

Ice shelves flow by gravity-driven straight distribution on the ocean surface. That flow frequently moves ice from the grounding line to seaward front of the shelf. The main mechanism of mass loss from ice shelves is iceberg calving, in which a large piece of ice breaks off from the seaward front of the shelf. Typically, a shelf front will extend forward for years or decades between major calving events. Snow buildup on the upper surface and melting from the lower surface are also imperative to the mass balance of an ice shelf.

The thinness of modern-day ice shelves ranges from about 100 to 1000 meters. The thickness similarity between solid ice and liquid water means that only about 1/9 of the floating ice is above the ocean surface. The world's main ice shelves are the Ross Ice Shelf and the Filchner-Ronne Ice Shelf in Antarctica.

Sunday, March 25, 2007

Poinsettia

The poinsettia, also identified as the Mexican flame leaf or Christmas star (Euphorbia pulcherrima), is a plant known for its striking red displays at Christmas time. It is often used as a floral Christmas decoration because of its festive colours.
The "flowers" are in fact large bunches of coloured leaves (modified bracts); the flowers themselves are in the center of each leaf bunch, but rather small and inconspicuous. Cultivars have been formed with orange, pale green, cream and marbled leaves. It is necessary that the plant receives no light at night between approximately October and Christmas. The slightest exposure to light during this critical period will often prevent "flowering".
Poinsettias are native to southern Mexico and Central America, where they may reach heights of sixteen feet. They are named after Joel Roberts Poinsett, the first United States ambassador to Mexico, who introduced the plant in the U.S. in 1825.

Tuesday, March 20, 2007

Camera

A camera is a device used to take pictures (usually photographs), also singly or in sequence, with or without sound, such as with video cameras. The name is derived from camera obscura, Latin for "dark chamber", an early mechanism for projecting images in which an entire room functioned much as the internal workings of a modern photographic camera, except there was no way at this time to record the image short of physically tracing it. Cameras may work with the visual spectrum or other portions of the electromagnetic spectrum.

Wednesday, March 14, 2007

Fog

Fog is a cloud in contact with the ground. Fog differs from other clouds only in that fog touches the surface of the Earth. The similar cloud that is not fog on lower ground may be fog where it contacts higher ground such as hilltops or mountain ridges. Fog is different from mist only in its density. Fog is defined as cloud which reduces visibility to less than 1 km, whereas mist is that which reduces visibility to less than 2 km.
The foggiest place in the world is the Grand Banks off the island of Newfoundland, Canada. Fog is common here as the Grand Banks is the meeting place of the cold Labrador Current from the north and the much warmer Gulf Stream from the south. The foggiest land areas in the world are Point Reyes, California and Argentia, Newfoundland, both with over 200 foggy days a year.

Fog

Fog is a cloud in contact with the ground. Fog differs from other clouds only in that fog touches the surface of the Earth. The similar cloud that is not fog on lower ground may be fog where it contacts higher ground such as hilltops or mountain ridges. Fog is different from mist only in its density. Fog is defined as cloud which reduces visibility to less than 1 km, whereas mist is that which reduces visibility to less than 2 km.
The foggiest place in the world is the Grand Banks off the island of Newfoundland, Canada. Fog is common here as the Grand Banks is the meeting place of the cold Labrador Current from the north and the much warmer Gulf Stream from the south. The foggiest land areas in the world are Point Reyes, California and Argentia, Newfoundland, both with over 200 foggy days a year.

Friday, March 09, 2007

Natural pearls

Natural pearls were found in many parts of the world. Present day natural pearling is confined frequently to seas off Bahrain. Australia also has one of the world's most recent remaining fleets of pearl diving ships. Australian pearl divers dive for south sea pearl oysters to be used in the cultured south sea pearl industry. The catch of pearl oysters is similar to the numbers of oysters taken throughout the natural pearl days. Hence large numbers of natural pearls are still found in the Australian Indian Ocean waters from wild oysters. X-Ray examination is required to absolutely verify natural pearls found today.
Natural pearls be 100% nacre. It is thought that natural pearls form under a set of unintentional conditions when a microscopic intruder or grain of sand enters an oyster (mollusk) and settles inside the shell. The oyster, being irritated by the intruder, secretes the pearl substance called nacre to cover the irritant. This process is repetitive for many years, thus producing a pearl.

Monday, March 05, 2007

Tourism in New York City

40 million foreign and American tourists visit New York City each year.Major destinations comprise of the Empire State Building, the Statue of Liberty, Broadway productions, scores of museums from the El Museo del Barrio to the Intrepid Sea-Air-Space Museum (closed until 2008 for repairs), Washington Square Park, the Bronx Zoo and New York Botanical Garden, luxury shopping along Fifth and Madison Avenues, and events such as the Halloween Parade in Greenwich Village, the Tribeca Film Festival, and free performances in Central Park at Summer stage. Many of the city's ethnic enclaves, such as Jackson Heights, Flushing, and Brighton Beach are major shopping destinations for first and second generation Americans up and down the East Coast.
New York City has 28,000 acres (113 km²) of parkland and 14 miles (22 km) of public beaches. Manhattan's Central Park, intended by Frederick Law Olmsted and Calvert Vaux, is the most visited city park in the United States.Prospect Park in Brooklyn, also planned by Olmsted and Vaux, has a 90 acre (36 Hectare) meadow. Flushing Meadows Park in Queens, the city's third largest, was the setting for the 1939 World's Fair and 1964 World's Fair.
New York's food culture, influenced by the city's immigrants and large number of dining patrons, is diverse. Jewish and Italian immigrants made the city famous for bagels and New York style pizza. Some 4,000 mobile food vendors approved by the city, many immigrant-owned, have made Middle Eastern foods such as falafels and kebabs standbys of contemporary New York street food.The city is also home to many of the finest haute cuisine restaurants in the United States.

Thursday, March 01, 2007

Monkey

A monkey is a member of either of two of the three groupings of simian primates. These three groupings are the New World monkeys, the Old World monkeys, and the apes. The New World monkeys are classified within the parvorder Platyrrhini, whereas the Old World monkeys (superfamily Cercopithecoidea) form part of the parvorder Catarrhini, which also includes the apes. Thus, methodically speaking, monkeys do not form a "natural group", in that the Old World monkeys are in fact more closely related to the apes than they are to the New World species. There are 264 known extant species of monkey. Because of their similarity to monkeys, apes such as chimpanzees and gibbons are often called monkeys in informal usage, though biologists don't consider them to be monkeys. Conversely, due to its size (up to 1 metre) the Mandrill is often thought to be an ape, but it is actually an Old World monkey. Also, a few monkey species have the word "ape" in their common name. Because they are not a single coherent group, monkeys do not have any particular traits that they all share and are not shared with the remaining group of simians, the apes.